1. Field of the Invention
Embodiments of the present invention relate to generally a laser oscillator. More particularly, embodiments of the present invention relate to methods and apparatuses for stabilizing the carrier envelope phase of the output of a laser oscillator.
2. Description of the Related Art
Chirped-pulse amplified (CPA) laser systems which are capable of producing high-energy sub 5 femtosecond (fs) pulses may be utilized in nonlinear optics and high-field physics applications such as high-harmonic generation using an oscillator beam, above-threshold ionization (ATI), Fourier synthesis of a multicolor laser, attosecond physics, high-frequency metrology, and, more broadly, biological imaging and medical surgery. In order to be effective in such applications, the carrier-envelope phase (CEP) of the output of the laser system must be stabilized for long periods of time. Often, the CEP is stabilized by locking the carrier-envelope offset frequency (fCEO). Approaches to locking the fCEO may include controlling the power output of the pump laser source with an acousto-optic modulator (AOM). However, due in part to the environmental conditions of the laser system equipment, the fCEO may slowly increase beyond the range of frequencies for which the AOM can compensate, thereby limiting the amount of time that the fCEO is locked and the CEP is stabilized.